Sunday, 6 June 2010

Adventures in beer design (Part IV)…..Grist for the Mill.

Time to decide what malts to use for my beer. These will make up what is called the “grist” or the “malt bill”. Basically the grist is the source of starch that is converted into sugar during mashing and is eventually converted to alcohol during fermentation. There are many different possible sources of this starch, in fact pretty much anything that contains starch can be used. However, in order to convert starch into sugar we need something called enzymes. These occur naturally in most grains and when, for example, barley grains decide to grow (or germinate) these enzymes are activated. They then break down the starch into sugar which provides a source of energy for the growing plant. Malting starts this process by inducing the germination of grains. Then just when the grain thinks it is free and growing the maltster puts it into hibernation by drying the grain (kilning). This leaves the grain full of enzymes but with little of the starch broken down into sugar. The brewer then reactivates the enzymes by milling the grains and mashing them with hot water. Free to do their job once again the enzymes break the starch down into sugar.

Most malt is lightly kilned which leaves the majority of starch and enzymes intact. Speciality malts are made by kilning at different temperatures and moisture. For example very dark malts are kilned at high temperatures to give a burnt, toasty, astringent flavour and dark colour. Crystal malt has a high moisture content when it is kilned and produces a caramelised, toffee flavour.

By mixing these malts together the brewer can influence the colour and some of the flavour of the final beer.

Non-barley sources of starch are known as adjuncts. These may take the form of wheat, rice, sorghum, maize etc. In Germany a law was introduced in 1516 called the Rheinheitsgebot that stipulated that beer could only be brewed from water, malt and hops. Much is made of this so called “purity” law but dig a bit deeper and you can see that it was a marketing stroke of genius as well as a political move. Basically it was a form of protectionism that banned beers made with adjuncts -this would include most UK and Belgian beers. What confuses me is that there are some German Wheat beers that claim to be brewed under this purity law – work that one out if you can! Tax probably came into it as well, indeed, the UK had a similar law at one time. When James II was deposed and fled to France, William of Orange introduced a tax on malted barley in 1697 to help pay for his wars. Not only that, but commercial brewers where prohibited from brewing beer with anything other than (taxed) malted barley. Scotland got away with it for a bit longer because of its strong support for James II. It was only in 1880 that William Gladstone passed the Free Mash Tun Act that allowed materials other than malted barley to be used. Anyway, in 1987 the European Union lifted the Rheinheitsgebot allowing adjuncts, once again, to be used in Germany. The law is still used as a marketing tool but I think it was a great shame that it was introduced in Germany and the UK because it meant that many types of beer became extinct. Indeed, if the rule hadn’t come into effect it is likely that the UK would have been producing wheat beers to rival the German, Dutch and Belgian ones.

I have digressed. Back to designing my beer. Because it is a Scottish ale I think it should have a good malty character. The majority of my grist will be pale ale malt (stock malt for most ale brews). To this I will add about 5% Crystal Malt for a toffee/caramelly flavour. Finally I will use some black or chocolate malt (I’ll start with 2%) whose astringency should partially balance out the malty notes and provide some deep colour. Some brewers use caramel to deepen the colour and add some flavour. I aim to avoid this and use an all grain extract. Once I have trialled this I will have the opportunity to make some adjustments and may even add some wheat. Wheat can help by bringing more neutral flavours as well as helping with head formation and retention on the final beer.

From the previous blog we saw that I need 1075⁰ of extract to make 20 litres of wort at an original gravity of 1043. Using the calculations I can work out the grist weights:Pale Ale Malt = (93% x 1150)/310 = 3.45 KgCrystal Malt = (5% x 1150)/260 = 0.22 Kg (220g)Chocolate Malt = (2% x 1150)/250 = 0.09 Kg (90g)

Using these figures I can estimate what the final colour will be. I say “estimate” because there are many factors which may influence colour. However, for a simple, uncomplicated brewer like myself a rough estimate will do.

Each malt comes with a specification not only of the theoretical extract as used above but also with a colour spec (it has many, many other specs but let’s keep things simple –ish). The colour specs for my malt may look something like this:

Pale Ale Malt = 6Crystal Malt = 160Chocolate Malt = 1000

The units for colour are EBC (or European Brewing Convention). The Americans have a different way of measuring and different units (SRM = Standard Reference Method) but seeing as I am in Europe then that is what I will use. (There is a conversion factor where SRM x 1.97 = EBC).

For each coloured ingredient in the mash tun:Multiply the weight in kg by the colour in EBCAdd the results for all the ingredients togetherThen multiply the total by 10 and then by the mash efficiency as a decimal fraction and then divide by the volume brewed.